Fiesole, in the hills north of Florence, is an ancient stronghold of the Etruscans (whose presence in the region provides the name Tuscany). But the low-lying ground on the banks of the Arno, marshy and prone to flooding, appear not to have been properly settled until well into the Roman period.

A colony is established here in the middle of the 1st century BC for veterans of Julius Caesar's campaigns. It is referred to a few years later as Colonia Florentina - the flourishing colony.

At this stage the name may have been as much a wish as a statement of fact. But a permanent bridge is built across the Arno at Florence early in the 1st century AD. Situated on the main route down the centre of Italy, linking the rich northern plains to the seat of power in Rome, Florence is well placed to flourish.

But the town's real expansion, at the expense of its neigbours, does not begin until the the late Middle Ages. Fiesole is violently seized in 1125 - beginning a process of expansion which eventually absorbs the whole of Tuscany.

Republican Florence: 12th - 16th century

When Florence begins its territorial expansion, in the 12th century, the town - like many others in northern Italy - is governed as a commune. The Florentines resist princely rule longer than any other commune apart from Venice, not finally succumbing until the Medici are accepted as dukes of Tuscany in the 16th century.

During the four centuries of the republic, Florence is in permanent turmoil as rival classes jockey for power. The city's astonishing achievement, not untypical in Italian history, is that amid the murder and the mayhem Florence grows prosperous and produces outstanding masterpieces of literature and art. Indeed this troubled city becomes the powerhouse of the Renaissance.

Florence's internal feuds are even more complex than those of other Italian cities. There is the usual clash between the nobles and the rich merchants and craftsmen of the city guilds. This struggle seems to be won by the merchants in 1282, when they pass a law restricting civic office to members of the guilds.

But the nobles continue to wield great power by other means (and even return to office by the subterfuge of becoming guild members themselves).

Meanwhile there is a similar struggle between the richer guilds and the lesser guilds, sometimes with the added complication of pressure from workers who are not allowed to join a guild. In 1378 there is an uprising by the Ciompi, who work for day wages in Florence's main industry, the manufacture of cloth.

On this occasion the labourers so frighten their employers that for a few weeks they are represented in the city's government - a brief experiment in something approaching democracy, until the new laws are revoked and Florence reverts to the commune's more normal oligarchy.

Factions within the ruling classes are aligned in Florence, as elsewhere in medieval Italy, in terms of support for the papal or imperial parties - Guelphs versus Ghibellines. Florence inclines mainly to the papal cause (putting it at regular risk from marauding imperial armies), but even this apparent unanimity does not prevent violent factionalism. The Guelphs of Florence divide into bitterly opposed groups, the Blacks (more energetic in their support of the pope) versus the Whites.

Individual lives are disrupted or cut short by these rivalries (as when Dante is exiled from Florence in 1301) but the city continues to prosper. It does so partly on wool. But Florence is also a city of bankers.

Bankers to Europe's kings: 13th - 14th century

During the 13th century bankers from north Italy, collectively known as Lombards, gradually replace the Jews in their traditional role as money-lenders to the rich and powerful. The business skills of the Italians are enhanced by their invention of double-entry book-keeping. Creative accountancy enables them to avoid the Christian sin of usury; interest on a loan is presented in the accounts either as a voluntary gift from the borrower or as a reward for the risk taken.

Siena and Lucca, Milan and Genoa all profit from the new trade. But Florence takes the lion's share.

Florence is well equippped for international finance thanks to its famous gold coin, the florin. First minted in 1252, the florin is widely recognized and trusted. It is the hard currency of its day.

By the early 14th century two families in the city, the Bardi and the Peruzzi, have grown immensely wealthy by offering financial services. They arrange for the collection and transfer of money due to great feudal powers, in particular the papacy. They facilitate trade by providing merchants with bills of exchange, by means of which money paid in by a debtor in one town can be paid out to a creditor presenting the bill somewhere else (a principle familiar now in the form of a cheque).

The ability of the Florentine bankers to fulfil this service is shown by the number of Bardi branches outside Italy. In the early 14th century the family has offices in Barcelona, Seville and Majorca, in Paris, Avignon, Nice and Marseilles, in London, Bruges, Constantinople, Rhodes, Cyprus and Jerusalem.

To add to Florence's sense of power, many of Europe's rulers are heavily in debt to the city's bankers. Therein, in the short term, lies the bankers' downfall.

In the 1340s Edward III of England is engaged in the expensive business of war with France, at the start of the Hundred Years' War. He is heavily in debt to Florence, having borrowed 600,000 gold florins from the Peruzzi and another 900,000 from the Bardi. In 1345 he defaults on his payments, reducing both Florentine houses to bankruptcy.

Florence as a great banking centre survives even this disaster. Half a century later great fortunes are again being made by the financiers of the city. Prominent among them in the 15th century are two families, the Pazzi and the Medici.

Florence's patrons: 1415-1430

At the time of the dominance of the Pazzi and the Medici, Florence is the pioneering centre of the Italian Renaissance. Both families are directly involved as patrons. In about 1430 Donatello produces the nude bronze of David for a Medici palace. In the same year Brunelleschi is starting work on the Pazzi chapel.

These two families are not the only enlightened patrons from the world of commerce. Brancacci, who pays for Masaccio's frescoes, is a silk merchant. Florentine guilds commission Donatello to provide sculptures for Orsanmichele. The Renaissance is a passion in this city - above all, perhaps, for Cosimo de' Medici.

Pater patriae: 1434-1464

From 1434 Cosimo de' Medici is unmistakably the most powerful man in Florence, even though his family's cause has suffered a severe setback in the previous year. In 1433 he is arrested by a rival faction. Bribes and well-placed friends save him from death. He is exiled for ten years, but from Venice he controls a Florentine party working for his return. It is only a year before they succeed. Cosimo is invited back, and his rivals are banished - more effectively - for life.

During a reign of 30 years, Cosimo uses his fortune to maintain absolute control over the internal affairs of Florence. Opponents find themselves squeezed to financial extinction.

Within the city this control is discreet. Outside, in relations with other powers, it is generally acknowledged that Cosimo is the ruler of Florence - by now a city state of considerable significance.

The expansion of Florentine control over the surrounding region accelerates before and during Cosimo's lifetime. Arezzo falls to a Florentine army in 1384. Pisa, a great prize, is taken in 1406. Livorno, of immense value as a seaport, is purchased in 1421.

These expansionist tendencies are mirrored by similar appetites in powerful neighbours to the north, Milan and Venice. Of the two Milan, at the turn of the century, is the more aggressive under the leadership of Gian Galeazzo Visconti. In 1402 Gian Galeazzo's sudden death saves Florence at the last moment from attack and probable capture by a Milanese army.

Four decades later, under Cosimo's leadership, Florence has her revenge. The Visconti are decisively defeated at Anghiari in 1440.

The defeat of the Milanese at Anghiari is soon followed by the end of the Visconti dynasty. The next ruler in Milan (from 1450) is a soldier of fortune, Francesco Sforza. Cosimo de' Medici now reverses the previous Florentine policy and makes an alliance with Milan (Sforza happens also to be a customer of the Medici bank). This is practical diplomacy between calculating statesmen. The encroachments of Venice are now seen by both rulers as the main threat in northern Italy.

Cosimo is interested in maintaining a balance of power between the Italian states, enabling commerce and the arts of peace to flourish in Florence. In this policy he is remarkably successful.

City of learning: 15th century

Florentine leadership in the arts is well established by the time of Cosimo's rise to power in 1434. His patronage brings much work to the city's painters, sculptors and architects. But he also greatly encourages another strand of the Renaissance in which Florence plays a major role - the scholarship of humanism.

This city, in which Petrarch first inspires Boccaccio with a love of the classics in 1350, already has a clear distinction in this field. Cosimo, who develops a passion for scholarly studies, has a firm foundation to build upon.

Cosimo founds three libraries in Florence, the greatest of them being the collection of books and manuscripts now known as the Laurentian library (because it is housed next to the church of San Lorenzo). It is during these same years that Cosimo's friend, the humanist pope Nicholas V, establishes the Vatican library.

The interest of both men extends beyond the Roman theme of the early Renaissance. They are fascinated also by the ideals of ancient Greece, and in particular by the philosophy of Plato.

Reliable manuscripts of Plato first become available in the west during Cosimo's lifetime. They are brought from Constantinople by Greek Orthodox churchmen and by Byzantine scholars, whose city is now under increasing threat from the Turks. In 1439 Florence has first-hand experience of these eastern scholars. At Cosimo's invitation, a council of the church moves from Ferrara to Florence to continue a debate between Roman Catholic and Greek Orthodox clerics on their long-standing doctrinal differences.

The rival churches eventually fail to agree. But the interest of Cosimo and of Florence in Greek culture is increased by the encounter.

Towards the end of his life Cosimo conceives a personal ambition to read all the works of Plato. He commissions their translation into Latin by a Florentine scholar, Marsilio Ficino. In 1462 he establishes an informal Platonic Academy in Florence, with Ficino at its head.

Ficino's Latin translation of the complete works of Plato is published in Florence in 1484, too late for Cosimo himself. But with the texts now widely available, Plato gradually recovers the leading role in philosophy which has been held since the time of Aquinas by Aristotle.

Ficino also translates many of the works of Neo-Platonism, including everything written by Plotinus. The result is an attempt, beginning in Florence but widely influential, to find a synthesis between Neo-Platonism and Christianity; Plato is seen as a Christian before his time. The mystical elements of Neo-Platonism become one of the major themes of Renaissance thought and art.

A famous result of this influence is the work of Sandro Botticelli, who has links with Ficino and the Platonic Academy.

Lorenzo the Magnificent: 1469-1492

Cosimo de' Medici dies in 1464. He is succeeded for five years by his son Piero, on whose death the leading citizens of Florence invite Piero's son Lorenzo, aged only twenty, to occupy the same informal position as ruler of the city. Lorenzo accepts what seems now almost a hereditary role. But he lacks his grandfather's skill either in running the family bank or in using his wealth to neutralize opposing factions.

The result, in 1478, is a conspiracy which nearly ends his rule.

A plot against Lorenzo and his younger brother Guiliano is hatched by a dangerous coalition. The conspirators include the Pazzi family (rival bankers), the archbishop of Pisa (a city restless under Florentine control) and a nephew of the pope, Sixtus IV. The pope has recently transferred the papal account from the Medici bank to the Pazzi and would prefer a more docile ruler in Florence.

The plot involves sacrilege and murder. The Medici brothers are to be struck down as they kneel before the altar during high mass in the cathedral in Florence. The signal for the assassination is to be the raising of the host.

In the event Giuliano is killed by one of the Pazzi clan, but Lorenzo escapes with a wound after fighting his way out of the cathedral. Florence remains loyal to the Medici. The conspirators are rounded up. By nightfall three of the Pazzi, together with the archbishop of Pisa in his ecclesiastical attire, are hanging from windows of Florence's government building, the Signoria.

But this is not the end of the crisis. The pope excommunicates Lorenzo de' Medici and persuades the king of Naples, Ferdinand I, to mount an expedition against Florence. During 1479 war drags painfully on, with losses of territory and the expense of maintaining a mercenary army in the field.

In December 1479 Lorenzo takes a step so bold that it would justify in itself the phrase by which history knows him - Lorenzo the Magnificent (in reality Il Magnifico is a title given quite commonly at the time to non-princely rulers of states). He travels secretly with a small party to Naples, placing himself recklessly in the king's power.

He argues to Ferdinand I that warfare between Italian powers increases the likelihood of a French invasion (the French claim upon Naples). Ferdinand is by now weary of a campaign more in the pope's interest than his own. Lorenzo returns to Florence with a peace treaty.

For the remaining twelve years of Lorenzo's life, Florence is stable and calm. But his proudest achievement, he writes in 1489, is an event of that year which could only have happened during the Renaissance papacy. He persuades the pope (by now Innocent VIII) to make his second son Giovanni a cardinal. Giovanni is thirteen.

In the long run Lorenzo is proved right. This event is of great significance in the Medici story. Giovanni becomes the first of two Medici popes, as Leo X, and the link with Rome greatly benefits the family. But in the shorter term, almost immediately after Lorenzo's death in 1492, the family fortunes crumble.

Piero and the exile of the Medici: 1492-1494

Lorenzo's son Piero is twenty in 1492 when he succeeds, without opposition, to his father's position of leadership in Florence. Lorenzo's relative inattention to the family bank means that Piero is the first Medici to attempt to control Florence without an ample supply of funds. And he lacks his father's diplomatic skills. Early in his reign he shows signs of abandoning Lorenzo's equal-handed relationship with Naples and Milan, inclining instead to Naples.

Ludovico Sforza, the duke of Milan, fears a shift in the balance of power. He invites the king of France to march through his territory and to claim the Angevin throne of Naples. The approach of the French king, Charles VIII, proves a disaster for Florence.

Charles VIII crosses the Alps in September 1494 with a massive army of 30,000 men. They pass peacefully through the territory of Milan and no doubt expect to do the same through Florence's Tuscan lands. France's quarrel is only with Naples.

But Florence has been recently identified as an ally of Naples. Sensing a crisis, the young Piero de' Medici imitates his father's famous act of personal diplomacy (his visit in 1479 to the king of Naples). Without informing the signoria, the official government of Florence, Piero makes his way to the camp of the French king.

In this encounter between two inexperienced young rulers, both in their early twenties, the Frenchman has the better of the bargain. Charles VIII emphasizes that all he wants is an assurance of Florence's good will, but adds that a convincing token of this would be the delivery into French hands of several key castles together with the ports of Pisa and Livorno. The records suggest that the French are astonished when Piero agrees.

So, when they hear of it, are the signoria in Florence. They protest that Piero has no authority to cede these Florentine possesssions, but it is too late. The French enter Florence and occupy Pisa (glad to be rid of the Florentine yoke) before moving on south.

When Piero returns to Florence, he is summoned to appear before the signoria. He makes the mistake of doing so with an armed guard. The city's bell is tolled to call the people to the piazza. A mob ransacks the Medici palace.

Piero and his two brothers escape from the city. It is nearly twenty years before his family returns. Meanwhile Florence has a leader in waiting of a very different kind. The Dominican friar Savonarola is on hand to transform worldly Florence into an austere city of God.

Savonarola: 1491-1498

In 1491 Savonarola becomes prior of the Dominican convent of San Marco in Florence. His powerful sermons, critical of decadence and luxury in both church and state (meaning papal Rome and the princely circle of the Medici) are already familiar in Florence, for he has been in the convent of San Marco on and off since 1482.

In spite of his savage voice, Lorenzo the Magnificent encourages this incorruptible man of God. Contrary to rumour, Savonarola blesses Lorenzo on his deathbed in 1492.

Savonarola foresees the likelihood of a French invasion, describing it as a punishment for Florence's sins. When it comes to pass in 1494, followed immediately by the exile of the Medici, the voice of the prophet is irresistible. Savonarola becomes the most powerful member of a group attempting to restore to Florence the strict virtues of republican piety.

For two years the citizens of Florence, under the new regime, enjoy an unprecedented degree of democratic involvement in their own affairs. They also, for a while, share Savonarola's puritanical zeal.

A famous bonfire of vanities, during the pre-Lent carnival season in 1497, is perhaps the peak of Savonarola's influence. People bring playing cards and games of chance, personal ornaments and lewd images, to fling into the flames. But fervour begins to pall. Even more relevant, the preacher's violent attacks on the Borgia pope, Alexander VI, cannot long go unanswered.

The pope makes various attempts to flatter and divert his critic, even offering him a cardinal's hat. But eventually Alexander VI resorts to traditional weapons - excommunication, charges of heresy, and the incitement of local groups in Florence hostile to Savonarola.

Two hot-headed friars open the gruesome final chapter of this story. In 1498 a Franciscan challenges to an ordeal by fire anyone who would defend Savonarola. The challenge is accepted by Fra Domenico, one of Savonarola's Dominican colleagues. The Florentine crowd eagerly awaits the public spectacle. The Franciscan fails to appear, so Fra Domenico has no need to step into the fire. But with the unreason of multitudes, it is Savonarola who is criticized. He has failed to work a miracle.

The next day a mob attacks the convent of San Marco, and hauls away Savonarola and Fra Domenico. They are examined, tortured, and tried with due ecclesiastical ceremony, before eventually being hanged and burned.

The Medici and Tuscany: 1512-1737

The fall of Savonarola, in 1498, does not bring the immediate return of the Medici. That is achieved some years later through the family's influence in Rome. In 1512 Giovanni de' Medici (of whose appointment as a boy cardinal his father Lorenzo was so proud) persuades the pope to restore the Medici to their position in Florence. They return with the help of a Spanish army.

In 1513 Giovanni himself becomes pope, as Leo X. His reign lasts eight years. After a brief intervening papacy of less than two years, another Medici - a cousin of Giovanni's - is elected as Clement VII. He reigns for eleven years, to 1534.

So for nineteen years out of twenty-one, during a time of turbulence and crisis in Italy, members of the Medici family occupy the papal throne and can benefit from the military support of Rome's allies - in particular Spain.

In 1527 republicans in Florence once more eject their Medici rulers. This final attempt to be rid of the family collapses in 1530 after an eleven-month siege of the city by a Spanish army. From now on there is no more pretence that this city state is a republic. In 1532 a new constitution establishes Alessandro de' Medici as the hereditary duke of Florence.

The murder of Alessandro in 1537 causes the leadership of the family to be transferred in that year to Cosimo, a member of a junior branch. With his emergence, the Medici family and the city of Florence begin to acquire a new identity.

In 1569 the pope creates Cosimo grand duke of Tuscany. During his reign the region, with Florence as its capital, incorporates the great prize of Siena (from 1557). The grand duchy of Tuscany now takes its place among the great dynasties of Europe. Two women, Catherine and Marie de Medici, play powerful roles on the European stage as queen consorts and regents of France.

The inheritance passes down peacefully within the ruling Medici family, to son or brother, until Gian Gastone dies without an heir in 1737. Thereafter the grand duchy becomes attached to the imperial house of Austria (by the treaty of Vienna in 1738).

Florence and Tuscany undergo upheavals during the Napoleonic period, followed by restoration of the grand duchy in the early 19th century. The mid-century brings the successful struggle to be free of Austrian rule and the establishment of the independent kingdom of Italy - of which Florence is the provisional capital, from 1865, until Rome is captured in 1870.